This invention relates to fluid tight connections, and more particularly to a fluid tight connection between concentric tubes or the like.
In many industrial applications, particularly in nuclear power related technologies, penetrations must be made in large vessels within which processes occur at high pressure. In the case of a nuclear reactor vessel, such penetrations are necessary for providing openings through which control rods or instrumentation may be inserted into the reactor core. Typically, nozzles are welded to the vessel wall to provide support surfaces on which other equipment associated with the manipulation of the control rods or instruments, may be mounted.
In many instances, a separate column or conduit passes concentrically within the nozzle and may be attached internally to the nozzle or to other structure within the vessel. Occasionally, the equipment mounted on the nozzle, or the column within the nozzle, must be removed for maintenance or repair. But during normal operation, it is required that a fluid-tight closure or connection be provided between the nozzle and the column contained therein, to prevent leakage of radioactive or otherwise environmentally disruptive fluid from within the vessel.
In one known method for connecting and sealing the column to the nozzle, metal-to-metal seals are actuated by "Marman" clamps (a product of the Aeroquip Corp., Los Angeles, CA.). Typically, a hydraulic tool is attached to a groove or to other mounting means in the nozzle or an adapter member on the nozzle, and is employed to seat the metal seals. After the seals are set, the Marman clamp halves are bolted together to maintain the seal in the compressed state. The hydraulic tool is then removed and an autoclave-type metal seal is then compressed by torquing several jacking screws around the perimeter of the nozzel. This technique is time-consuming and requires holding close tolerances.